| 摘要 |
A safety valve includes a housing defining first and secondary piston bores in fluid communication with each other via a port, a first piston movably arranged within the first piston bore and having a first piston rod extending longitudinally therefrom and coupled to a flow tube, and a second piston movably arranged within the secondary piston bore and having a secondary piston rod extending longitudinally therefrom and axially engageable with the flow tube, wherein hydraulic fluid pressure acts on the first piston until the first piston axially moves and exposes the port, whereby the hydraulic fluid pressure is then able to enter the secondary piston bore and also act on the second piston. |
